Environment, Science, Technology, United States

Ammonia is being developed as a low-carbon fuel

ENVIRONMENT

Intro: A start-up in America is developing world’s first ammonia-powered ships

THE Brooklyn Navy Yard’s sprawling industrial complex once employed 70,000 workers to build US battleships and aircraft carriers during the second world war. Almost 80 years later, it has become home to a New York city firm with a very different maritime mission – harnessing ammonia as a low-carbon fuel for the global shipping industry.

The start-up Amogy has already shown how ammonia-powered technology can work in a flying drone, a John Deere tractor and most recently a truck. Now, it is working on an ammonia-powered ship.

Most ships currently run on fossil fuels that emit greenhouse gases, accounting for 3 per cent of the world’s carbon emissions. One alternative involves converting vehicles to hydrogen power that would only emit water. But hydrogen gas needs to be compressed and liquified at -253°C for storage and transportation.

Ammonia could serve as an alternative hydrogen-bearing fuel that is more easily stored and transported in a stable liquid form at room temperature.

Hydrogen can be extracted by heating ammonia to high temperatures, which is a process that comes with its own energy cost. This is where Amogy’s technology comes in. To make ammonia power more viable, the company has developed what it describes as a more efficient and miniaturised “ammonia cracking” method that can chemically extract hydrogen from ammonia at a lower temperature. It uses a proprietary catalyst to speed up the process inside a chemical reactor that feeds into a hydrogen fuel cell.

A leading chemist at Saint Mary’s College of California says that what Amogy was able to bring to the table is that by having better catalytic technologies (all proprietary) they were able to miniaturise their ammonia cracking units and put them on board vehicles.

It was in July 2021 when Amogy first showed that its system could supply 5 kilowatts of power to a drone. By comparison, a standard ammonia cracking system for extracting that amount of hydrogen power is usually the size of a large shipping container. It also paved the way for a 100-kilowatt tractor demonstration in May 2022. That was followed by a 300-kilowatt truck demonstration in January 2023. The firm is now working towards demonstrating a 1-megawatt system in a tugboat.

Many countries already have pipelines and port facilities for handling ammonia that is produced industrially as fertiliser for agriculture. The US alone has more than 5000 kilometres of ammonia pipelines compared with 2500 kilometres of pipeline for transporting hydrogen – though it will need more to support ammonia-powered vehicles.

Another challenge is that ammonia still “has a carbon footprint associated with the production” because the standard industrial process uses natural gas. Low-carbon ammonia production would require use of carbon capture.

Cleaner alternative methods could ideally use electricity from renewable power sources to split water into hydrogen for conversion to ammonia.

. Science Book: Chemistry

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Research, Science

Scientists reveal that the proton’s size is moveable

PARTICLE PHYSICS

Intro: The radius of the proton, a subatomic particle, seems to vary depending on how you look at it

THE proton, one of the building blocks for all matter, is proving to be an awkward customer to size up. If you look at its charge, it will have one radius, but if you look at its mass, you will see a different, smaller radius.

A new picture of the proton is emerging. In the 1960s, experiments that fired electrons at protons revealed that the latter contained point-like, electrically charged particles that we now call quarks. A proton has two up quarks and a down one. Quarks were later found to be bound together by particles called gluons.

We now know more about quarks and how far their electric field extends in space, which is sometimes called the radius of the proton. But we know less about gluons, which contain most of the mass of the proton in the form of energy, because they are chargeless, and so much harder to investigate. Seeing how they are distributed can tell us about how the proton’s mass is arranged and its structure.

Scientists at the Argonne National Laboratory in Illinois have probed the proton’s gluons with particles called J/psi mesons. This is possible because even though gluons don’t have electric charge, they have a property called colour charge, which comes from the strong nuclear force, one of the universe’s four fundamental forces. J/psi mesons are made up of a charm quark and its antiquark, which also have colour charge and so are capable of interacting with gluons.

The researchers fired a beam of photons at liquid hydrogen, which is comprised mainly of just protons, and the photons interacted with the protons. These collisions produced short-lived J/psi mesons. By measuring how many of these were produced, the research team could calculate the proton’s mass distribution using quantum mechanical models that describe gluon-quark interactions.

Their results suggest that the gluons’ mass is confined to a dense core in the proton’s centre, while the charge from the quarks extends to a second, larger radius.

They also compared their results with predictions from another model of the proton, which agreed in some places and diverged at others, suggesting that the new figures need validating with more precise experiments or one that probe proton structure in a different way.

If it is confirmed, it will be a very interesting finding because it tells us something quite deep about how the proton’s constituents behave from a spatial point of view.

A different internal structure could have implications for calculating other proton properties, such as spin, angular momentum and energy distribution, which many sensitive experiments rely on. But some of the new proton findings rest on models used to calculate them, which haven’t proved entirely reliable in the past.

The results follow another revelation about the proton’s internal structure. Last year, a research team found that the proton can contain a much heavier charm quark, in addition to the three regular quarks, but asked: ‘Does the mass radius become larger or smaller?’

. Further understanding on quarks can be found:

Science Book: Physics

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